How to determine the encoder is broken?

A lot of friends whether confusion rotary encoder is broken? Electronic today to tell everyone about the following several ways to teach everyone to distinguish the stand or fall of rotary encoder. 1. PLC with a rotary encoder, check the pulse number or code values correct? 2. Use rotary encoder by oscilloscope waveform. 3. The multimeter gear test output voltage is normal? 4. : the output of the encoder for the NPN measure the positive and the signal output power supply line, the transistor set ON the output voltage closer to the power supply voltage, the transistor set OFF when the output voltage is close to 0 v. 5. Encoder for PNP output: when the measured anode and the signal output power supply line, the transistor set ON the output voltage is close to the power supply voltage, the transistor set OFF when the output voltage is close to 0 v judging through the above five direction detection, we can quickly determine the rotary encoder is broken, the hope can help you, if the question can be free to contact us for your answer.